Chapter 19

Ecology

the study of how organisms interact with each other and with their environment

Populations

individuals of the same species that live together in the same place

Communities

populations of different species that live together in the same place

Population Size

the number of individuals in a population

Population Density

how crowded a unit area is of individuals

Growth Rate

the difference between birth rates and death rates

Exponential Growth

growth rate remains constant and population experiences rapid growth

Logistic Growth

the growth rate stabilizes at carrying capacity

Carrying Capacity

the maximum number of individuals that an area can support

Density-Independent Effects

factors that affect a population regardless of the population size/density

Density-Dependent Effects

factors that depend on the size of the population

Life History

an organism’s complete life cycle

R-Selected Adaptations

favor a high growth rate; populations living in rapidly changing environments

K-Selected Adaptations

help organisms thrive at carrying capacity; populations living in more stable and competitive habitats

Type I Survivorship Curve

mortality is highest for old individuals

Type II Survivorship Curve

mortality is relatively the same for all ages of individuals

Type III Survivorship Curve

mortality rate is the highest for young individuals

Community

the mix of species that are at any given place

Niche

an organisms biological role in a community/their pattern of living

Habitat

the place where an organism lives

Interspecific Competition

competition between different species

Intraspecific Competition

competition within the same species

Principle of Competitive Exclusion

a species the uses resources more efficiently will eventually eliminate the other

Coevolution

the adaptation of two or more species in a community

Mutualism

a symbiotic relationship in which both species benefit

Commenalism

a symbiotic relationship that benefits one species but neither hurts nor helps the other

Parasitism

a symbiotic relationship in which one species benefits while the other is harmed

Predation

the consuming of one organism by another

Succession

the orderly replacement of one community with another

Primary Succession

occurs on bare, lifeless substrates (no soil)

Pioneering Community

the first community to be established

Secondary Succession

occurs after an already established community as been disturbed